Projectors are apparatuses which project enlarged images to a screen via a projection lens once image input signals of various display devices.
Projectors may be categorized into a PRT (CRT) type, liquid crystal display (LCD) type and digital light processing (DLP) type. Recently, LCD type projectors have been popular because of an advantage of connection with PCs.
According to the LCD type projector, light which is generated from a light source lamp passes a transparent LCD panel to display images on a front screen.
FIG. 1 is a perspective view of a conventional projector. The projector shown in FIG. 1 includes a projection lens part 10′ provided on a front surface of a wide box shaped housing 20 such that generated images may be projected via the projection lens part.
An optical system of the projector includes a lightening part, a micro device and a projection lens part. The lightening part generates and emits light. The micro device realizes three dimensional images by using the light. The projection lens projects the images. The micro device may be a transparent LCD panel to receive an image input signal from an outside and to display images, if the projector is a LCD type.
The projector 100′ shown in FIG. 1 is wide box-shaped with a large horizontal area. As a result, the above projector 100′ should be installed on an auxiliary table or on the ceiling. A thin type projector has been introduced with an improvement of the optical system and the thin type projector means a thin box-shaped projector.
FIG. 2 illustrates an embodiment of the thin type projector. This thin type projector 100′ includes a projection lens part 10′ provided at a front surface of an upright box-shaped housing 20′, with an exposed lens.
As shown in FIG. 2, this thin type projector may a stand type which uses a stand 50′ or a wall-mount type. Even if this thin projector is a stand type, this thin projector has a small horizontal area than the conventional projector shown in FIG. 1. If it is a wall mount type, this thin type projector is simpler to install than the conventional projector installed in the ceiling.
The thin projector receives an image input signal of various kinds display devices and projects enlarged images to a screen via the projection lens. Here, the various display devices may provide a sound input signal, rather than the image signal. The display devices supply the image signal to a TV, DVD player, portable multimedia player (PMP) or PC. An auxiliary sound device should be provided if it is necessary to amplify a small capacity of a speaker of the display device, for example, a lap top computer and if a portable display device without a speaker is connected with the thin type projector.
While the conventional projector turned on, images are projected from the projection lens part. While the conventional projector is turned off, a separate private usage cover is mounted to the projection lens to protect the projection lens part from dust, scratches or shocks.